Photocatalytic Degradation of Michler's Ketone in Water by UV Light Illumination Using TiO<sub>2</sub> Photocatalyst: Identification of Intermediates and the Reaction Pathway

Lu, Chung‐Shin; Mai, Fu-Der; Wu, Yi-Chin; Yao, I-Chun; Hsu, Peng-Yueh; Chen, Chiing‐Chang

doi:10.1002/jccs.200900109

Cited by 8 publications

(2 citation statements)

References 40 publications

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“…2a). According to a different mechanism proposed for Michler ketone demethylation (Lu et al 2009), the initial step of the reaction is radical attack to the hydrogen atom from the N(CH 3 ) 2 group. It is worth to note that the thermodynamic stability of reactive organic species like radicals and carbocations is an important factor determining which reaction pathway is more kinetically favored.…”

Section: Resultsmentioning

confidence: 99%

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Studziński

Gackowska

Przybyłek

et al. 2017

Environ Sci Pollut Res

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In order to protect the skin from UV radiation, personal care products (PCPS) often contain chemical UV-filters. These compounds can enter the environment causing serious consequences on the water ecosystems. The aim of this study was to examine, the effect of different factors, such as UV light, the presence of NaOCl and H2O2 on the formaldehyde formation during popular UV filter, 2-ethylhexyl 4-(dimethylamino)benzoate (ODPABA) demethylation. The concentration of formaldehyde was determined by VIS spectrophotometry after derivatization. The reaction mixtures were qualitatively analyzed using GC/MS chromatography. The highest concentration of formaldehyde was observed in the case of ODPABA/H2O2/UV reaction mixture. In order to describe two types of demethylation mechanisms, namely, radical and ionic, the experimental results were enriched with Fukui function analysis and thermodynamic calculations. In the case of non-irradiated system containing ODPABA and NaOCl, demethylation reaction probably proceeds via ionic mechanism. As it was established, amino nitrogen atom in the ODPABA molecule is the most susceptible site for the HOCl electrophilic attack, which is the first step of ionic demethylation mechanism. In the case of irradiated mixtures, the reaction is probably radical in nature. The results of thermodynamic calculations showed that abstraction of the hydrogen from N(CH3)2 group is more probable than from 2-ethylhexyl moiety, which indicates higher susceptibility of N(CH3)2 to the oxidation.Electronic supplementary materialThe online version of this article (doi:10.1007/s11356-017-8477-8) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Studziński

Gackowska

Przybyłek

et al. 2017

Environ Sci Pollut Res

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“…The degradation parameters of PIs in water environments have also been explored. As a dominant congener, BP in aquatic environments can be degraded by microbes or UV/H 2 O 2 . , OH free-radical-initiated degradation reactions include hydroxylation, carboxylation, and ring cleavage. Photodegradation of MK by UV/TiO 2 has also been evaluated in lab studies.…”

Section: Occurrence Of Pismentioning

confidence: 99%

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Ji,

Liang,

Liu

et al. 2023

Environ. Sci. Technol.

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Photoinitiators (PIs) are a family of anthropogenic chemicals used in polymerization systems that generate active substances to initiate polymerization reactions under certain radiations. Although polymerization is considered a green method, its wide application in various commercial products, such as UV-curable inks, paints, and varnishes, has led to ubiquitous environmental issues caused by PIs. In this study, we present an overview of the current knowledge on the environmental occurrence, human exposure, and toxicity of PIs and provide suggestions for future research based on numerous available studies. The residual concentrations of PIs in commercial products, such as food packaging materials, are at microgram per gram levels. The migration of PIs from food packaging materials to foodstuffs has been confirmed by more than 100 reports of food contamination caused by PIs. Furthermore, more than 20 PIs have been detected in water, sediment, sewage sludge, and indoor dust collected from Asia, the United States, and Europe. Human internal exposure was also confirmed by the detection of PIs in serum. In addition, PIs were present in human breast milk, indicating that breastfeeding is an exposure pathway for infants. Among the most available studies, benzophenone is the dominant congener detected in the environment and humans. Toxicity studies of PIs reveal multiple toxic end points, such as carcinogenicity and endocrine-disrupting effects. Future investigations should focus on synergistic/antagonistic toxicity effects caused by PIs coexposure and metabolism/transformation pathways of newly identified PIs. Furthermore, future research should aim to develop “greener” PIs with high efficiency, low migration, and low toxicity.

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Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO₂ Catalyst under UV and Visible Light

Shi

Lai

Yao

et al. 2012

J Chinese Chemical Soc

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The catalysts of un-doped, single-doped and co-doped mesoporous titanium dioxide (MTiO 2 ) were prepared by a template method with tetrabutyltitanate (Ti(OC 4 H 9 ) 4 ) as a Ti source material and Pluronic P123 as a template. The photo-absorbance of the obtained catalysts was measured by UV-vis absorption spectroscopy, and the photocatalytic activities of the prepared samples under UV and visible light were estimated by measuring the degradation rate of methyl orange (MO) (50 mg/L) in an aqueous solution. It was shown that the co-doped MTiO 2 could be activated by visible light and could thus be used as an effective catalyst in photo-oxidation reactions. The effect of Fe and Ce co-dopants on the material properties was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N 2 adsorption-desorption isotherm measurement. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of ca. 10 nm with high surface area of ca. 150 m 2 /g. The photocatalytic activity of MTiO 2 co-doped with Fe and Ce was markedly improved due to the synergistic actions of the two dopants. CHEMICAL SOCIETY Fig. 8. Degradation curves of MO with visible light.Experimental conditions: initial concentration of MO 50 mg/L, solution pH 4, dosage of catalyst 1.0 g/L, calcination temperature 500°C. Fig. 9. The cyclic performance of 0.5% Fe, 0.5% Ce-MTiO 2.

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Photocatalytic Degradation of Michler's Ketone in Water by UV Light Illumination Using TiO₂ Photocatalyst: Identification of Intermediates and the Reaction Pathway

Cited by 8 publications

References 40 publications

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO₂ Catalyst under UV and Visible Light

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Photocatalytic Degradation of Michler's Ketone in Water by UV Light Illumination Using TiO2 Photocatalyst: Identification of Intermediates and the Reaction Pathway

Cited by 8 publications

References 40 publications

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Studies on the formation of formaldehyde during 2-ethylhexyl 4-(dimethylamino)benzoate demethylation in the presence of reactive oxygen and chlorine species

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO2 Catalyst under UV and Visible Light

Contact Info

Product

Resources

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Photocatalytic Degradation of Michler's Ketone in Water by UV Light Illumination Using TiO₂ Photocatalyst: Identification of Intermediates and the Reaction Pathway

Photocatalytic Activity of Fe and Ce Co‐doped Mesoporous TiO₂ Catalyst under UV and Visible Light